LED illumination linear constant current driving circuit
Technical field
The present invention relates to a kind of LED illumination products using the linear constant current driving circuit, are suitable for LED illumination, especially
Suitable for using aluminium sheet as the optoelectronic integration product of carrier.
Background technology
On LED illumination product, linear constant current drive scheme is widely adopted.In general, being shone in the LED of linear constant current driving
In bright equipment, the element and LED particle of linear constant current driving circuit are welded on aluminium sheet, LED and linear constant current driving circuit
The heat of generation is transmitted to via aluminium sheet on shell.
There is larger parasitic capacitance between the conductive layer and metal layer of aluminium sheet, immunity to interference is being carried out to LED illumination product
When test, applies the electric signal of Fast transforms between alternating current and shell, can cause to flow through leakage current in the parasitic capacitance of aluminium sheet,
The leakage current on each element of linear constant-current drive circuit and can generate overvoltage on LED, when the overvoltage is more than linear constant current
When the absolute rating of each element of driving circuit and LED, LED illumination driving circuit or LED will be damaged.
Therefore, it is necessary to a kind of linear constant current driving circuits that can absorb overvoltage.
Invention content
The present invention provides a kind of LED illumination linear constant current driving circuits, to overcome the deficiencies of existing technologies, in solution
State technical problem.
The present invention provides a kind of LED illumination linear constant current driving circuit, including a rectifier, the first overvoltage crowbar,
One LED unit, several linear current sources and the energy release circuit being made of several LED;The input terminal of rectifier connects
Alternating current exports as anode and ground;LED unit is powered by the anode of rectifier, current controlled in several linear current sources;If
The anode of dry linear current source is connected to LED unit, cathode ground connection;First overvoltage crowbar has the first turn-on threshold,
One end is grounded, and the other end is connected to the anode of several linear current sources via energy release circuit.
Further, the present invention provides a kind of LED illumination linear constant current driving circuit, also has following characteristics:When arbitrary
When the cathode voltage of linear current source is more than the first turn-on threshold, energy release circuit conducting, the cathode voltage of linear current source
It is clamped at the first turn-on threshold.
Further, the present invention provides a kind of LED illumination linear constant current driving circuit, also has following characteristics:Also include one
Second overvoltage crowbar, one end connect the anode of rectifier, and the other end is connected with the ungrounded end of the first protection circuit.
Further, the present invention provides a kind of LED illumination linear constant current driving circuit, also has following characteristics:Second overvoltage
Protect circuit that there is the second turn-on threshold;When rectifier anode voltage is more than the sum of the first turn-on threshold and the second turn-on threshold
When, the cathode voltage of rectifier is clamped at the sum of the first turn-on threshold and the second turn-on threshold.
Further, the present invention provides a kind of LED illumination linear constant current driving circuit, also has following characteristics:Energy discharges
Circuit includes several diodes;Arbitrary between the anode of linear current source and the ungrounded end of the first overvoltage crowbar
Electrical connection is equivalent to one or more diode series/parallels.
Further, the present invention provides a kind of LED illumination linear constant current driving circuit, also has following characteristics:First overvoltage
Protection circuit is the combination of one or more of Zener diode, Transient Suppression Diode, varistor, capacitance.
Further, the present invention provides a kind of LED illumination linear constant current driving circuit, also has following characteristics:Second overvoltage
Protection circuit is the combination of one or more of Zener diode, Transient Suppression Diode, varistor, capacitance.
Further, the present invention provides a kind of LED illumination linear constant current driving circuit, also has following characteristics:Second overvoltage
Protection circuit is a resistance, and shunt resistance flows into the electric current of the first overvoltage crowbar from rectifier anode via LED unit,
Avoid LED unit overcurrent damage.
The effect of invention:
The present invention provides a kind of LED illumination linear constant current driving circuit, when external disturbance source leads to linear current source both ends
Voltage be more than overvoltage crowbar both ends voltage when, discharge overcurrent energy to overvoltage crowbar on, avoid linear electricity
Stream source punctures.
Description of the drawings
Fig. 1 is the schematic diagram of the LED illumination linear constant current driving circuit of embodiment one.
Fig. 2 is the schematic diagram of the LED illumination linear constant current driving circuit of embodiment two.
Fig. 3 is the schematic diagram of the LED illumination linear constant current driving circuit of embodiment three.
Fig. 4 is the schematic diagram of the LED illumination linear constant current driving circuit of example IV.
Fig. 5 is the schematic diagram of the LED illumination linear constant current driving circuit of embodiment five.
Specific implementation mode:
Below in conjunction with the drawings and specific embodiments, the present invention will be further described.
Embodiment one
Fig. 1 is the schematic diagram of the LED illumination linear constant current driving circuit of embodiment one.
As shown in Figure 1, LED illumination linear constant current driving circuit includes:One rectifier BD1, the first overvoltage crowbar
LED unit LED1, three linear current sources I11, I12, I13 and the energy release circuit that SPD11, one are made of several LED
DA1。
The input terminal of rectifier BD1 connects alternating current, exports as anode+and ground-.LED unit LED1 by rectifier BD1 just
Pole powers, current controlled in linear current source I11, I12, I13.The anode of linear current source I11, I12, I13 are separately connected
To LED unit, cathode is grounded-.
First overvoltage crowbar SPD11 has the first turn-on threshold, and the first overvoltage crowbar SPD11 can be Zener
One or more of diode, Transient Suppression Diode, varistor, capacitance combine.First overvoltage crowbar SPD11 mono-
End ground connection-, the other end is connected to positive I31, I32, I33 of three linear current sources via energy release circuit DA3.
In the present embodiment, energy release circuit DA1 includes three diodes.The anode of three diodes respectively with anode
The anode connection of I11, I12, I13, cathode are all connect with the ungrounded end of the first protection circuit SPD11.
When the cathode voltage of any one linear current source is more than the first turn-on threshold of the first overvoltage crowbar SPD11
When, energy release circuit DA1 conductings, the cathode voltage of linear current source is clamped at the first turn-on threshold.
Embodiment two
Fig. 2 is the schematic diagram of the LED illumination linear constant current driving circuit of embodiment two.
As shown in Fig. 2, LED illumination linear constant current driving circuit includes:One rectifier BD2, the first overvoltage crowbar
LED unit LED2 that SPD21, the second overvoltage crowbar SPD22, one are made of several LED, three linear current source I21,
I22, I23 and an energy release circuit DA2.
The input terminal of rectifier BD2 connects alternating current, exports as anode+and ground-.LED unit LED2 by rectifier BD2 just
Pole powers, current controlled in linear current source I21, I22, I23.The anode of linear current source I21, I22, I23 are separately connected
To LED unit LED2, cathode is grounded-.
First overvoltage crowbar SPD21 has the first turn-on threshold, and the first overvoltage crowbar SPD21 can be Zener
One or more of diode, Transient Suppression Diode, varistor, capacitance combine.First overvoltage crowbar SPD21 mono-
End ground connection-, the other end is connected to positive I21, I22, I23 of three linear current sources via energy release circuit DA2.
When the cathode voltage of any one linear current source is more than the first turn-on threshold of the first overvoltage crowbar SPD21
When, energy release circuit DA2 conductings, the cathode voltage of linear current source is clamped at the first turn-on threshold.
Second overvoltage crowbar SPD22 has the second turn-on threshold, and the second overvoltage crowbar SPD22 can be neat
Receive one or more of diode, Transient Suppression Diode, varistor, capacitance combination.Second overvoltage crowbar SPD22
The anode of one end connection rectifier BD2+, the other end is connected with the ungrounded end of the first protection circuit SPD21.
In the present embodiment, energy release circuit DA2 includes three diodes.The anode of three diodes respectively with anode
The anode connection of I21, I22, I23, cathode are all connect with the ungrounded end of the first protection circuit SPD21.
When rectifier BD2 cathode voltages are more than the sum of the first turn-on threshold and the second turn-on threshold, rectifier BD2 is just
Pole tension is clamped at the sum of the first turn-on threshold and the second turn-on threshold, and LED2 is avoided to damage.
Embodiment three
Fig. 3 is the schematic diagram of the LED illumination linear constant current driving circuit of embodiment three.
As shown in figure 3, LED illumination linear constant current driving circuit includes:One rectifier BD3, the first overvoltage crowbar
LED unit LED3 that SPD31, the second overvoltage crowbar SPD32, one are made of several LED, three linear current source I31,
I32, I33 and an energy release circuit DA3.
Other than the circuit structure of energy release circuit DA3 and two difference of embodiment, the circuit connection of other devices and
Function is identical, is not repeated to describe.
In the present embodiment, energy release circuit DA3 includes the first diode D31, the second diode D32 and third diode
D33.The anode of first diode D31 is connect with the positive I31 of linear current source, and cathode is non-with the first protection circuit SPD31's
Ground terminal is connected.The anode of second diode D32 is connect with the positive I32 of linear current source, cathode and the first diode D31's
Anode connection.The anode of third diode D33 is connect with the positive I33 of linear current source, and cathode and the second diode D32 are just
Pole connects.
Example IV
Fig. 4 is the schematic diagram of the LED illumination linear constant current driving circuit of example IV.
As shown in figure 4, LED illumination linear constant current driving circuit includes:One rectifier BD4, the first overvoltage crowbar
LED unit LED4 that SPD41, the second overvoltage crowbar SPD42, one are made of several LED, three linear current source I41,
I42, I43 and an energy release circuit DA4.The circuit connection of each device in the present embodiment and function is identical and embodiment three
It is identical, it is not repeated to describe.
In the present embodiment, the first overvoltage crowbar SPD41 includes:First Transient Suppression Diode D41 and the first capacitance
C41.The plus earth of first Transient Suppression Diode D41, cathode are connected with the circuit of energy release circuit DA4.First capacitance
C41 is connected in parallel on the both ends of the first Transient Suppression Diode D41.
In the present embodiment, the second overvoltage crowbar SPD42 includes:Second Transient Suppression Diode D42 and the second capacitance
C42.The anode of second Transient Suppression Diode D42 is connected with the circuit of energy release circuit DA4, and cathode is with rectifier BD4's
Anode is connected.Second capacitance C42 is connected in parallel on the both ends of the second Transient Suppression Diode D42.
Embodiment five
Fig. 5 is the schematic diagram of the LED illumination linear constant current driving circuit of embodiment five.
As shown in figure 5, LED illumination linear constant current driving circuit includes:One rectifier BD5, the first overvoltage crowbar
LED unit LED5 that SPD51, the second overvoltage crowbar SPD52, one are made of several LED, three linear current source I51,
I52, I53 and an energy release circuit DA5.The circuit connection of each device in the present embodiment and function is identical and embodiment three
It is identical, it is not repeated to describe.
In the present embodiment, the second overvoltage crowbar SPD52 is resistance R5.The one end resistance R5 and energy release circuit DA5
Circuit be connected, the other end is connected with the anode of rectifier BD5.Resistance R5 shuntings are flowed into from rectifier BD5 anodes via LED5
The electric current of first overvoltage crowbar SPD51 avoids LED unit LED5 overcurrent damages.
Embodiments above only describes the main feature and innovative point of this programme.Those skilled in the art should
Solution, this programme are not restricted to the described embodiments.Under the premise of not departing from the innovation point and protection domain, this programme also has
Various change, these changes and improvements are fallen in the claimed range of this programme.The claimed range of this programme by
Appended claims and its equivalent limit.
It should be noted that above-described embodiment be in order to illustrate rather than limitation the present invention, those skilled in the art will
It is enough that many alternative embodiments are designed under conditions of without departing substantially from scope of the appended claims.Word "comprising" be not excluded for those with
The presence for the different element or step of element or step listed in claim.Word "a" or "an" before element is not arranged
Except the presence of multiple this elements, in enumerating several circuit claims, several in these devices can be by one come table
Existing, hardware branch is also same, merely because certain methods describe in different dependent claims, does not illustrate these
The combination of method cannot be used for making a profit.
It should be noted that herein, the first and second equal relational terms be used merely to an entity or
Person operates to be distinguished with another entity or operation, is appointed without necessarily requiring or implying existing between these entities or operation
What this actual relationship either sequence moreover, term "comprising", " comprising " or any other variant be intended to it is non-exclusive
Property include so that the process, method, article or equipment comprising a series of elements not only include those elements, but also
Further include the other element that those are expressly recited, or further include for this process, method, article or equipment it is intrinsic
Element, term " connected ", " connection ", " being connected to " or other variants include not only being connected directly two entities,
Include being connect by being indirectly connected with other entities beneficial to improvement.